The genus Nonnapsylla Wagner, 1938 (Craneopsyllinae) includes only 1 species, Nonnapsylla rothschildi Wagner, 1938. Two subspecies are recognized by the shape of the dorsal margin of the helmet, apical shape of the spines in helmet and genal combs, length of first and fourth segments of the maxillary palpus, and shape of the hilla of the spermatheca. The validity of the characters used to separate the 2 subspecies of Nonnapsylla rothschildi Wagner, 1938 is discussed based on information from the literature, as well as from direct observation of type specimens and specimens collected in northwestern Argentina. We conclude that Nonnapsylla rothschildi wagneri Johnson, 1957 should be considered as a synonym of the nominal subspecies. We also extend the southern limits of the distribution of the species and report its presence in Argentina.